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Impact of Immigration and Assimilation on Public Transit Ridership and Single-Vehicle Commuting to Work

The rapid growth of immigration has substantially changed the commuter mix in many metropolitan areas. However, prior studies by the proposed investigators have indicated that immigrants' travel behavior is not stable and that travel behavior shifts dramatically within 10-20 years residence in the U.S. As a result, transportation managers in California and other parts of the U.S. face a hazardous environment for service planning. The only metropolitan area in the U.S. with a long enough record of experience serving a long-settled immigrant population is New York. Of course, the experience of that region may not serve well as a guide to travel behavior in a decentralized region such as Los Angeles or other California cities. In fact, it is more likely that Los Angeles's experience in the last 20 years can be the prototype that serves as a better guide for other growing and decentralized urban areas. Unfortunately, as reviewed below, very little is known about the travel behavior of immigrants in California as they assimilate over time. This creates greater uncertainty when planning transportation investments in areas with growing immigrant populations. The proposed study can provide much needed guidance about changes to expect in aggregate demands for transportation services. Under Area 2, Mobility of Urban Populations, the proposed project objectives are two-fold. The first is to estimate the impact of immigrants in transit use and on single-vehicle occupancy, observing this in California, the US as a whole, and the top 10 immigrant-receiving states, as well as in the 50 largest metropolitan areas. Distinctions will be made between immigrants who are longer settled and those who have resided less than 10 years in the U.S., as well as between those of different genders, race-ethnic groups or with other characteristics. The second objective is to statistically estimate the impact of immigration on mode choice in 2000 and to estimate the effect of assimilation processes since 1990. As immigrants' lengthen their duration in the U.S., a process of assimilation is likely to occur. However, it is not known how much it may converge with the transportation behavior of the native-born population and how much of this adjustment process may be simply governed by changes in income or personal earnings over time. Although immigration has had growing, even dominant, impact on urban population growth in the past few decades, there is little empirical research on the impacts of immigration on transportation mode choice and how this is changing over time. It is common knowledge in metropolitan areas like Los Angeles that immigrants, particularly those who are more recently arrived, comprise a significant share of those using public transportation as their means of journey to work. However, no published research to date has quantified how immigrants affect public transit use and how they may assimilate to driving alone as their duration in the U.S. increases. This project will use the 1990 and 2000 censuses to track the impacts of immigration on transit ridership and on intensity of roadway use. The project will also estimate the transportation mode choice of immigrants, how this has changed with growing length of residence, and how much impact immigrant assimilation has on mode choice net of other demographic and income factors.